we're here. what's going on here? we're here. and they got the deal done. >> reporter: they got that deal done, and went on to three more years sharing success, controversy, even tragedy as close partners. >> and i think, you know, there are not a lot of people in the world who go through what they do, and, you know, it's the president h.w. bush/bill clinton relationship, it's carter/ford, mcenroe/connors, whatever it is, when you're on the court after the fact, you're like, hey, you're more like me than not. we're bonding. for good or bad, we've been put together. and it's always going to be like that. >> from rivals to partners, the evolution of this friendship has been something to watch over the last four-plus years. and is now entering a new phase as president obama takes on his send term, and hillary clinton heads towards her last day as a top member of his cabinet. kate bolduan, cnn, washington.